How and where to use guide
VELUX Twin and Combination Flashings 78x118cm EBP MK06 0021B
Typical applications and suitability
This flashing system is designed for dual roof window installations on pitched roofs with conventional tile or slate coverings. It is most commonly used in loft conversions, attic spaces, and residential extensions where two windows need to be installed side by side or in a stacked combination arrangement. The integrated design makes it particularly suitable for new-build installations and major renovation projects where multiple windows are planned during the initial roof design phase. The 78x118cm dimensions are engineered to work with standard VELUX window sizes in these configurations.
- Dual or combination roof window installations on pitched roofs
- New-build loft conversions and attic spaces
- Residential extensions with multiple window requirements
- Standard tile and slate roof coverings only
Installation and fitting procedure
Installation requires careful planning and precise alignment to ensure the weathertight seal functions correctly. The flashing must be positioned so that the upper section sits beneath the roof covering above the windows, whilst the lower section sits above the roof covering below. Secure fixing to the roof structure is critical and must be carried out according to VELUX installation instructions. The integrated design means components are pre-assembled, reducing the number of separate fixings required on site. All fixings must be sealed appropriately to prevent water ingress. Alignment of both window frames within the flashing unit must be checked before final securing.
- Position upper flashing section beneath roof covering above windows
- Ensure lower section sits above roof covering below windows
- Secure all fixings to roof structure with appropriate sealing
- Check alignment of both window frames before final fixing
- Follow VELUX installation instructions for your specific roof type
Maintenance and long-term performance
Once installed, the flashing requires minimal maintenance but should be inspected annually, particularly after severe weather. Check that all fixings remain secure and that the weathertight seal has not been compromised. Debris such as leaves and moss should be cleared from the flashing edges and any guttering associated with the installation. Do not attempt to adjust or reposition the flashing after installation, as this may break the weathertight seal. If leaks develop, do not attempt temporary repairs; contact a qualified installer to inspect and remedy the issue professionally.
- Inspect annually for loose fixings or seal damage
- Clear debris from flashing edges and associated guttering
- Do not reposition or adjust after installation
- Contact a qualified installer if leaks develop
Important limitations and on-site considerations
This flashing system is designed exclusively for pitched roofs with tile or slate coverings and must not be used on flat roofs or other roof types. The pre-engineered dimensions mean it is not suitable for non-standard window spacing or custom arrangements. Installation in high-exposure locations or areas subject to severe weather should be assessed by a qualified surveyor or installer before purchase. The flashing does not include the roof windows themselves; these must be ordered separately. Delivery and handling on site should be careful to avoid damage to the flashing edges, which could compromise the weathertight seal.
- Pitched roofs with tile or slate coverings only
- Not suitable for flat roofs or alternative roof types
- Requires standard window spacing and combination arrangements
- Handle carefully on site to avoid edge damage
- Windows must be ordered separately